# Checking that email is unique

**URL:** <https://community.glideapps.com/t/checking-that-email-is-unique/69439>\
**Category:** Ask for Help\
**Created:** [January 10, 2024, 9:33am UTC](https://community.glideapps.com/t/checking-that-email-is-unique/69439 "2024-01-10T09:33:17Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![MattGlides](https://avatars.discourse-cdn.com/v4/letter/m/53a042/32.png) [@MattGlides](https://community.glideapps.com/u/MattGlides)\
**Post date:** [January 10, 2024, 9:33am UTC](https://community.glideapps.com/t/checking-that-email-is-unique/69439/1 "2024-01-10T09:33:18Z")

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When a User is adding a new customer, they add an email address which writes to an email column.  
I want to check that email against all other emails in that column already, and they should be unable to proceed if the email they entered matches one that’s already in our data.  
How would I go about doing this on the data side? I know how to set it up in the layout but I cannot figure out the data side of it.

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**Author:** ![Darren\_Murphy](https://sea2.discourse-cdn.com/flex002/user_avatar/community.glideapps.com/darren_murphy/32/47326_2.png) [@Darren\_Murphy](https://community.glideapps.com/u/Darren_Murphy)\
**Post date:** [January 10, 2024, 9:41am UTC](https://community.glideapps.com/t/checking-that-email-is-unique/69439/2 "2024-01-10T09:41:29Z")

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You need to use a custom form. Capture the email in a user specific column, then use that in a relation matching with the existing data. If the relation is not empty, don’t allow the user to save the record.

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**Author:** ![ThinhDinh](https://sea2.discourse-cdn.com/flex002/user_avatar/community.glideapps.com/thinhdinh/32/49_2.png) [@ThinhDinh](https://community.glideapps.com/u/ThinhDinh)\
**Post date:** [January 10, 2024, 2:52pm UTC](https://community.glideapps.com/t/checking-that-email-is-unique/69439/3 "2024-01-10T14:52:07Z")

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> [@How do I create a custom form?](https://community.glideapps.com/t/how-do-i-create-a-custom-form/25014):
>
> I’m just dropping this here so I have something to refer people to when they ask. This is a simple concept app (copyable), that demonstrates the following techniques: Building custom forms for adding and editing list items (as an alternative to the native forms provided by Glide) Preventing duplicate new entries using [User Specific Columns](https://docs.glideapps.com/all/reference/data-editor/user-specific-columns) and [Relations](https://docs.glideapps.com/all/reference/data-editor/computed-columns/relation-column) Enforcing mandatory input items The use of visibility conditions and user specific booleans to control user flow There is nothing particular…

Here’s how to build a custom form.